This invention relates to medico-surgical devices for facilitating insertion of a tube or similar device to the pharynx.
The invention is more particularly concerned with devices for facilitating the insertion of tubes or the like into the pharynx of a patient.
It is common practice to use an airway known as a laryngeal mask for the administration of anaesthetic and ventilation gases to a patient. These airways comprise a tube with a mask or cuff at one end, the tube being inserted in the patient's mouth so that one end is located in the hypopharynx and so that the mask forms a seal in this region with the surrounding tissue. Laryngeal masks have several advantages over endotracheal tubes which are longer and seal with the trachea below the vocal folds. One problem, however, with laryngeal masks is that insertion can cause trauma to the pharyngeal wall. This is because the tip of the mask has a tendency to stick in the pharynx as a result of the sharp turn it has to negotiate before it seats itself in the hypopharynx. These problems have been reported in, for example, Anaesthesia 1989; 44: 703 by van Heerden and Kirrage. Although the risk of damage can be reduced by ensuring that the head of the patient is correctly positioned during insertion, where the anaesthetist is not completely familiar with the correct technique, there is still an associated risk of trauma. Blood is often seen on the laryngeal mask when it is removed, even when the anaesthetist is experienced in the technique.